intergral proteins span the membrane; peripheral proteins project from the membranes outer surface; transmembrane proteins extend outside the cell membranes at one end and dips into the cytoplasm interior

Two rod-like centriles-Used to produce cilia and flagella-Distributes chromosomes during cell division

Cilia

-Short hair-like projection-Propel substances on cell surface

Flaglellum

-Long tail-like projection-Provides motility to sperm

Microfilaments & Microtubules

-Thin rods and tubules-Support cytoplasm- Allows for movement of organelles-Found in all cells

Intermediate Filaments

-Found in specialized cells-Form a strong inner scaffolding that helps cells attach and form a barrier

Inclusions

-Temporary nutrients (glycogen & lipids) and pigments (melanin)

Disease at the Organelle Level

ALD (adrenoleukodystrophy)-Peroxisomes lack the 2nd most abdumdant protein in the outer membrane of this organelle which usually tansports an enzyme into the peroxisome-The enzyme controls breakdown of a type of ver long chain fatty acids-W/o the enzyme, the fatty acids build up in cells in the brain and spinal chord stripping them of myelin

-Is the movement of molecules thru a membrane by hydrostatic pressure that is > on one side of the membrane than the other-Smaller molecules are forced thru porous membranes-Hydrostatic pressure important in the body (Heartbeart)-Molecules leaving blood capillaries

What is the definition of hydrostatic pressure in A&P?

created by the weight of water due to gravity -forces water molecules thru to the other side

Active Transport

Carries substances across a membrane from regions of lower concentration to higher concentration (requires energy)

Primary Active Transport

-ATP is used directly-Energy to drive solutes across membranes is from and electrochemical gradient that is created by pumping ions out of cells-Two main forms: counter-transport (antiport) co-transport (symport)

Counter-transport

-2 species of ions or other solutes are pumped in opposite directions across a membrane-One of these is allowed to flow from high to low concentration which drives the transport of the other solute from low to to high concentration

Co-transport

-Uses the flow of one solute to from and area of high to low concentration to move another molecule against its preferred direction of flow-Both solutes move in the same direction across the membrane-Ex: glucose symporter cotransports 2 sodiums from every molecule of glucose that it imports into the cell

-Cell engulfs a substance by forming a vesicle around the substane. 3 types:Pinocytosis: substance is mostly waterPhagocytosis: substance is solidReceptor-mediated endocytosis: needs the substance to bind to a membrane-bound receptor and are enclosed in vesicles

Transcytosis (active transport)

-Encocytosis followed by exocytosis (=transcytosis)-Transports a substance rapidly thri a cell-HIV crossing a cell layer

The Cell Cycle

-Series of changes a cell undergoes from the time it forms until the time it divides-Stages: Interphase Mitosis Cytokinesis (sytoplasmic division) Differentiation

-Can divide to form 2 new stem cells (self renewel and characteristic of a stem cells)-Can divide to forma stem call and a progenitor cell-Totipotent: can give rise to every cell typePluripotent: can give rise to a restriced # of cell types

Progenitor Cells

-Comminuted cell-Can divide to become an of a restriced number of cells-Pluripotent

What is common about all cells in the human body

all cells (EXCEPT RBCs) have the same set of genetic instructions, but as cells specialize - they use some genes and ignore others Bone cells and muscle cells differ in structure & function b/c each expresses a different subset